go/analysis/passes/stdmethods: recognize any as alias for interface{}, for errors.As check

Now that any is an alias for interface{}, we need to recognize both

	func (T) As(any) bool
	func (T) As(interface{}) bool

as satisfying errors.As.

For golang/go#33232.

Change-Id: Ie5a992c37da8020e80367528bc23370227a70f75
Reviewed-on: https://go-review.googlesource.com/c/tools/+/369954
Trust: Russ Cox <[email protected]>
Run-TryBot: Russ Cox <[email protected]>
gopls-CI: kokoro <[email protected]>
Reviewed-by: Robert Findley <[email protected]>

Author: rsc

go/analysis/passes/stdmethods/stdmethods.go

@@ -61,7 +61,7 @@ var Analyzer = &analysis.Analyzer{
 // we let it go. But if it does have a fmt.ScanState, then the
 // rest has to match.
 var canonicalMethods = map[string]struct{ args, results []string }{
-	"As": {[]string{"interface{}"}, []string{"bool"}}, // errors.As
+	"As": {[]string{"any"}, []string{"bool"}}, // errors.As
 	// "Flush": {{}, {"error"}}, // http.Flusher and jpeg.writer conflict
 	"Format":        {[]string{"=fmt.State", "rune"}, []string{}},                      // fmt.Formatter
 	"GobDecode":     {[]string{"[]byte"}, []string{"error"}},                           // gob.GobDecoder
@@ -194,7 +194,9 @@ func matchParams(pass *analysis.Pass, expect []string, actual *types.Tuple, pref
 func matchParamType(expect string, actual types.Type) bool {
 	expect = strings.TrimPrefix(expect, "=")
 	// Overkill but easy.
-	return typeString(actual) == expect
+	t := typeString(actual)
+	return t == expect ||
+		(t == "any" || t == "interface{}") && (expect == "any" || expect == "interface{}")
 }
 
 var errorType = types.Universe.Lookup("error").Type().Underlying().(*types.Interface)

go/analysis/passes/stdmethods/testdata/src/a/a.go

@@ -47,14 +47,18 @@ type E int
 
 func (E) Error() string { return "" } // E implements error.
 
-func (E) As()     {} // want `method As\(\) should have signature As\(interface{}\) bool`
+func (E) As()     {} // want `method As\(\) should have signature As\((any|interface\{\})\) bool`
 func (E) Is()     {} // want `method Is\(\) should have signature Is\(error\) bool`
 func (E) Unwrap() {} // want `method Unwrap\(\) should have signature Unwrap\(\) error`
 
 type F int
 
 func (F) Error() string { return "" } // Both F and *F implement error.
 
-func (*F) As()     {} // want `method As\(\) should have signature As\(interface{}\) bool`
+func (*F) As()     {} // want `method As\(\) should have signature As\((any|interface\{\})\) bool`
 func (*F) Is()     {} // want `method Is\(\) should have signature Is\(error\) bool`
 func (*F) Unwrap() {} // want `method Unwrap\(\) should have signature Unwrap\(\) error`
+
+type G int
+
+func (G) As(interface{}) bool // ok

go/analysis/passes/stdmethods/testdata/src/a/b.go

@@ -0,0 +1,12 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+// +build go1.18
+
+package a
+
+type H int
+
+func (H) As(any) bool // ok

go/analysis/passes/stdmethods/testdata/src/typeparams/typeparams.go

@@ -28,14 +28,14 @@ type E[P any] int
 
 func (E[_]) Error() string { return "" } // E implements error.
 
-func (E[P]) As()     {} // want `method As\(\) should have signature As\(interface{}\) bool`
+func (E[P]) As()     {} // want `method As\(\) should have signature As\((any|interface\{\})\) bool`
 func (E[_]) Is()     {} // want `method Is\(\) should have signature Is\(error\) bool`
 func (E[_]) Unwrap() {} // want `method Unwrap\(\) should have signature Unwrap\(\) error`
 
 type F[P any] int
 
 func (F[_]) Error() string { return "" } // Both F and *F implement error.
 
-func (*F[_]) As()     {} // want `method As\(\) should have signature As\(interface{}\) bool`
+func (*F[_]) As()     {} // want `method As\(\) should have signature As\((any|interface\{\})\) bool`
 func (*F[_]) Is()     {} // want `method Is\(\) should have signature Is\(error\) bool`
 func (*F[_]) Unwrap() {} // want `method Unwrap\(\) should have signature Unwrap\(\) error`